The present invention relates to an image processing system, a projector, a program, an information storage medium, and an image processing method capable of correcting the shape of an image.
There may be a case where an image is distorted depending on the relative angle formed by the optical axis of light projected from an image projection device such as a projector and a projection target such as a screen, whereby keystone distortion occurs in the vertical direction or the horizontal direction.
Therefore, an image display device must display an image in an undistorted state.
A conventional projector with an image correction function corrects only distortion of an image in the vertical direction using a built-in angle sensor, but cannot correct distortion of the image in the horizontal direction.
As a method for correcting distortion of an image in the horizontal direction, Japanese Patent Application Laid-open No. 2002-44571 proposes a method of allowing a user to indicate four corners of a screen using a mouse or the like and causing a projector to semi-automatically correct distortion of an image based on the indicated information.
Japanese Patent Application Laid-open No. 2002-247614 discloses a projector which determines the external shape of a screen using a sensing section and corrects an image so that the external shape of the image becomes the same as the determined external shape.
However, if a projector changes the shape of an image into the external shape of a screen as disclosed in Japanese Patent Applications Laid-open No. 2002-44571 and Japanese Patent Applications Laid-open No. 2002-247614, the image after being changed has an external shape differing from the external shape of the original image. In this case, since an observer has the impression that the displayed image differs from the original image, it is undesirable to employ such a processing method.
Moreover, it is desirable that an image be displayed at a desired aspect ratio even when using the height/width ratio of the projection target as a reference.